1. Field of the Invention
The present invention relates to a semiconductor device with multilevel interconnection structure and a manufacturing method thereof, and more particularly, it relates to a semiconductor device with a multilevel interconnection whose wiring capacitance is reduced and a manufacturing method thereof.
2. Description of the Related Arts
There is observed an effective wherein as the wiring pitch becomes smaller, and the distance between adjacent wires becomes shorter, the wiring capacitance increases as a semiconductor device becomes more minute. When the wiring capacitance increases, the operational speed of a circuit becomes slower, the electric power consumed becomes larger. Therefore, for reducing wiring capacitance, it is required to use a low dielectric constant film as an interlayer insulating film.
An inorganic SOG (Spin-on-glass) such as HSQ (hydrogen silsesquioxane) has a comparatively low dielectric constant of approximately 3.0, and further, it has a thermal resistance of approximately 400.degree. C., and therefore, it is a very useful material. However, the dielectric constant of HSQ is still high when compared with that of an organic film, and it is desired to further lower this dielectric constant of HSQ. As a method to reduce the dielectric constant of an inorganic SOG film, for example, there is a method shown in "Study of Porous Interlayer Insulating Film Material" Aoi, et al. (Proceedings of the 52th symposium on Semiconductor and Integrated Circuits Technology, pp. 62-67 (1997), in which silylation is performed by adding a silylation agent to an SOG solution, coupled with, amine processing the resulting dielectric constant is lowered to approximately 2.3, the diameter of a pore is made fine, and humidity resistance is improved.
However, in the above conventional semiconductor device with multilayer structure, solution processing is troublesome, and there is also a problem in stability of wiring capacitance.
In Japanese Patent Laid-Open Publication No. 8-250490, a method is disclosed, where a thin film of a modified HSQ thin film precursor is coated on a semiconductor substrate with a conductor. This HSQ thin film precursor comprises a hydrogen silsesquioxane resin, and preferably a modifier selected from among the group consisting of alkylalkoxysilane, alkylalkoxysilane fluoride, and a combination thereof. However, the prior art described in this publication also has a weak point because solution processing is troublesome and the stability of wiring capacitance is low.